Gary, lists,
There's a new article on beta decay and biochemical chiral asymmetry:
Chirally Sensitive Electron-Induced Molecular Breakup and the
Vester-Ulbricht Hypothesis
Phys. Rev. Lett. 113, 118103 – Published 12 September 2014
J. M. Dreiling and T. J. Gay
Abstract
[ http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.113.118103 ]
We have studied dissociative electron attachment in sub-eV
collisions between longitudinally polarized electrons and chiral
bromocamphor molecules. For a given target enantiomer, the
dissociative Br anion production depends on the helicity of the
incident electrons, with an asymmetry that depends on the electron
energy and is of order 3×10−4. The existence of chiral sensitivity
in a well-defined molecular breakup reaction demonstrates the
viability of the Vester-Ulbrict hypothesis, namely, that the
longitudinal polarization of cosmic beta radiation was responsible
for the origins of biological homochirality.
DOI: http://dx.doi.org/10.1103/PhysRevLett.113.118103
There's a perhaps over-excitingly titled article posted at Sciam from
_Nature_ about the new paper:
Weak Nuclear Force Shown to Give Asymmetry to Biochemistry of Life
"Left-handed" electrons have been found to destroy certain
organic molecules faster than their mirror versions
http://www.scientificamerican.com/article/weak-nuclear-force-shown-to-give-asymmetry-to-biochemistry-of-life/
Best, Ben
On 9/30/2014 5:05 PM, Gary Richmond wrote:
Ben, Edwina, Helmut, lists,
I can see from your responses that these issues of chirality and
genuine (vs degenerate) triadic relations might be approached from a
number of angles. I hope I haven't opened a can of worms by broaching
them taken together, although it would appear that Peirce was
attempting just that in the passage earlier quoted.
For now, I would say that I can't but help agree with Peirce that
/genuine/ triadic relations only occur in the biologic and
intellectual realms, while I leave the possibility of degenerate
semiosis occurring before life as an open question. Gardner discusses
chirality and the advent of life in several chapters, most especially
in chptr. 15, "The origin of life."
What I remember most from Gardner's book is his emphasis on two of the
greatest scientific advances of the century as involving chirality:
namely, physics' overthrow of parity (chptr 22, "The fall of parity")
and biology's discovery of the corkscrew nature of the molecule
carrying the genetic code chptr. 14, "Living molecules").
Gardner's pretty good on the philosophical history of thinking about
chirality and has some illuminating passages reflecting on Kants,
Pasteur's, Japp's, de Nouy's, and others' understandings of it, as
well as the thinking of more contemporary philosophers and,
especially, scientists from Pauli through to those working in
superstring theory (btw, 4 of the 5 current versions of superstring
theory involve chirality).
As for the matter-antimatter matter, it's discussed in Gardner's book
here and there in several chapters and especially in chptrs. 21,
"Antiparticles" and 26, "Where's the antimatter?," but I too, while I
read quite a bit in about it a decade or so ago, am hardly an expert.
For now, I'll conclude with a brief quote from Gardner's book which
may /very tentatively/ connect some of the questions your posts
brought up, at least for me In a discussion of "weak interactions"
Gardner writes:
[O]ne cannot completely rule out the possibility that whatever is
responsible for the asymmetry of weak interactions may also play a
role in the formation of primitive organic compounds.
That thought will have me up half the night! Maybe that's enough for
one post.
Best,
Gary
*Gary Richmond
Philosophy and Critical Thinking
Communication Studies
LaGuardia College of the City University of New York
C 745
718 482-5690*
On Tue, Sep 30, 2014 at 4:05 PM, Benjamin Udell wrote:
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